14t on front. 40t on back
chain: 525 , sprockets: 16/43
15 and 45
630 pitch, 96 links
The chain is size 530, and the stock gearing is 15/45, meaning that the front sprocket has 15 teeth and the rear sprocket has 45 teeth.
17 tooth front, 42 tooth rear, 110 link chain, size 530
Sprocket and chain and what?
The chain length needed is determined by chainring size, sprocket size and the design of your frame. There's no way of saying that you'll need from the sprocket alone. On top of that there isn't much to choose from when it comes to half links. They are all of the same length and in width there are two options 1/8" or 3/32". You need one the same width of your chain.
You need a chain meant for single-speed or internally geared bikes, cut to the right length.
The chainring by the pedals and the sprocket(s) by the rear wheel.
Both, cranshaft to camshaft sprocket, belt, camshaft sprocket to cams, chain.
Normally that indicates a worn out sprocket. Replace and you should be OK.
A minimum plain bore sprocket is a roller chain sprocket with a hole drilled through the center. A finished bore sprocket is a roller chain sprocket with a hole drilled through the center augmented by either a keyway or set screws.